【HDOJ】1160 FatMouse's Speed

DP。

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#define MAXNUM 1005

typedef struct {
    int w, s;
    int index;
} mouse_st;

mouse_st mouses[MAXNUM];
int dp[MAXNUM], next[MAXNUM];

int comp(const void *a, const void *b) {
    mouse_st *p = (mouse_st *)a;
    mouse_st *q = (mouse_st *)b;
    if (p->w == q->w)
        return p->s - q->s;
    else
        return q->w - p->w;
}

int main() {
    int n=0, m, beg;
    int i, j, max, index;

    while (scanf("%d %d", &mouses[n].w, &mouses[n].s) != EOF) {
        mouses[n].index = n;
        ++n;
    }

    memset(dp, 0, sizeof(dp));
    qsort(mouses, n, sizeof(mouse_st), comp);
    for (i=0; i<n; ++i)
        next[i] = i;
    m = 0;

    for (i=0; i<n; ++i) {
        max = 0;
        for (j=0; j<i; ++j) {
            if (mouses[j].w>mouses[i].w && mouses[j].s<mouses[i].s) {
                if (max < dp[j]) {
                    max = dp[j];
                    index = mouses[j].index;
                }
            }
        }
        if (max)
            next[mouses[i].index] = index;
        dp[i] = max + 1;
        if (m < dp[i]) {
            m = dp[i];
            beg = mouses[i].index;
        }
    }
    if (m == 1)
        printf("1\n1\n");
    else {
        printf("%d\n", m);
        while (next[beg] != beg) {
            printf("%d\n", beg+1);
            beg = next[beg];
        }
        printf("%d\n", beg+1);
    }

    return 0;
}